document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=220972>Question 220972</A>: <I><SPAN STYLE=\"word-break: break-all;\"> plane flies 420 mph in still air. With wind, a trip from a to b takes 10 minutes less than the return trip flying against wind from b to a. Distance between a to b is 360 miles. Find speed of wind. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #165933 by </B><A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><B>ankor@dixie-net.com(22740)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/cgi-bin/show-face.mpl?user=ankor@dixie-net.com><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=165933\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> plane flies 420 mph in still air. With wind, a trip from a to b takes 10 minutes<BR>\n" );
document.write( " less than the return trip flying against wind from b to a.<BR>\n" );
document.write( "Distance between a to b is 360 miles. <BR>\n" );
document.write( "Find speed of wind.<BR>\n" );
document.write( ":<BR>\n" );
document.write( "Let w = speed of the wind<BR>\n" );
document.write( "then<BR>\n" );
document.write( "(420+w) = speed with the wind<BR>\n" );
document.write( "and<BR>\n" );
document.write( "(420-w) = speed against the wind<BR>\n" );
document.write( ":<BR>\n" );
document.write( "Convert 10 min to <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1%2F6 ALIGN=MIDDLE  ALT=\"1%2F6\"   DISABLED_style= \"max-width:90%; height:auto;\" > hr<BR>\n" );
document.write( ":<BR>\n" );
document.write( "Time b-a - Time a-b = 10 min<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=360%2F%28%28420-w%29%29 ALIGN=MIDDLE  ALT=\"360%2F%28%28420-w%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > - <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=360%2F%28%28420%2Bw%29%29 ALIGN=MIDDLE  ALT=\"360%2F%28%28420%2Bw%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1%2F6 ALIGN=MIDDLE  ALT=\"1%2F6\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Multiply equation by 6(420-w)(420+w)<BR>\n" );
document.write( ":<BR>\n" );
document.write( "6(420-w)(420+w)*<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=360%2F%28%28420-w%29%29 ALIGN=MIDDLE  ALT=\"360%2F%28%28420-w%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > - 6(420-w)(420+w)*<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=360%2F%28%28420%2Bw%29%29 ALIGN=MIDDLE  ALT=\"360%2F%28%28420%2Bw%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 6(420-w)(420+w)*<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1%2F6 ALIGN=MIDDLE  ALT=\"1%2F6\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( ":<BR>\n" );
document.write( "Cancel the denominators and you have<BR>\n" );
document.write( "6(420+w)*360 - 6(420-w)*360 = (420+w)(420-w)<BR>\n" );
document.write( ";<BR>\n" );
document.write( "2160(420+w) - 2160(420-w) = 176400 - w^2<BR>\n" );
document.write( ":<BR>\n" );
document.write( "1327200 + 2160w - 1327200 + 2150w = 176400 - w^2<BR>\n" );
document.write( ":<BR>\n" );
document.write( "Combine on the left to form a quadratic equation:<BR>\n" );
document.write( "w^2 + 4320w - 176400 = 0<BR>\n" );
document.write( "You have to use the quadratic formula to find w<BR>\n" );
document.write( ":<BR>\n" );
document.write( "I got a positive solution of w = 40.4545 mph<BR>\n" );
document.write( ";<BR>\n" );
document.write( ":<BR>\n" );
document.write( "Check this with a calc<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=360%2F%28%28420-40.4545%29%29 ALIGN=MIDDLE  ALT=\"360%2F%28%28420-40.4545%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > - <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=360%2F%28%28420%2B40.4545%29%29 ALIGN=MIDDLE  ALT=\"360%2F%28%28420%2B40.4545%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1%2F6 ALIGN=MIDDLE  ALT=\"1%2F6\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( ".9485 - .7818 = .1667<BR>\n" );
document.write( ".1667 = .1667<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );